Lights status on router what do they mean?

Constantly losing wireless internet connection... two lights on router go off altogether when this happens.... ADSL is off, internet is off, the WLAN button blinks and power light is solid (on)

PC is in a different room (upstairs) I'm waiting for a very long Ethernet cable to arrive, just to try to establish if it is the connection or the computer (XP) but I have tried two and same happens on both.
Talk Talk say its not the line, it is a shared phone/PC line.

I found it easier to use a self installed telephone extension upstairs (25 metres) and plug the router into that near the desktop.
I get some drop outs due, I think due to router age. When it happens unplug for 15 secs or so. As above what make and which ISP ? Being upstairs the router range increases and I found no reduction iin speed compared to plugging in to original BT socket